The permanent styling of keratin-containing fibers is usually achieved by mechanically deforming the fibers and setting the style using suitable auxiliary means. Before and/or after this styling, the fibers are treated with a keratin-reducing preparation. After a rinsing process, the fibers are then treated in the so-called setting step with an oxidizing agent preparation and rinsed, and the styling aids (rollers, foam curlers) are removed after or during the setting step. If a mercaptan, e.g., ammonium thioglycolate, is used as a keratin-reducing component, then it cleaves a portion of the disulfide bridges of the keratin molecule into thiol groups, thus resulting in the softening of the keratin fibers and the swelling of the fibers under enlargement of the fiber diameter. During the subsequent oxidative setting, disulfide bridges are again linked in the hair keratin, thereby setting the keratin structure in the specified deformation. Alternatively, it is known to use sulfite instead of mercaptans for hair styling. By means of hydrogen sulfite solutions and/or sulfite solutions and/or disulfite solutions, disulfide bridges of the keratin are cleaved in a sulfitolysis process according to the equationR—S—S—R+HSO3(+)→R—SH+R—S—SO3(+) thus softening the keratin fibers. Hydrogen sulfite, sulfite, and disulfite-containing reducing agents do not have the strong intrinsic odor of the mercaptan-containing agents. As described above, the cleavage can be reversed in a setting step with the aid of an oxidizing agent under formation of new disulfide bridges.
If, in addition to the reshaping, a coloration of the keratinic fibers is also desired, the coloration can be performed as a separate treatment before or after reshaping. Particularly in the case of oxidative coloration, however, this results in extreme stressing of the keratinic fibers, since any oxidative treatment of the fibers damages their internal structure. What is more, such an approach is very time-consuming, since a time span of 2 or more weeks should be provided between the reshaping and the color treatment in order to avoid the aforementioned extreme stresses and associated damage. A number of methods for the simultaneous reshaping and coloring of keratinic fibers, particularly hairs, have therefore been proposed. In many cases, an oxidizing agent preparation is used for this purpose in the setting step which includes direct dyes and/or oxidation dye precursors in addition to the oxidizing agent. Such an approach is described, for example, in DE19713698 C1. However, this approach has the disadvantage that the coloration takes place at the same time as the setting—that is, it occurs at a point in time at which the fibers to be treated are subjected to the mechanical stress of the styling aids. This impedes the uniform application of the dyes, thus resulting in the danger of an uneven coloring result.
EP 0352375 A1 and EP 1287812 A2 disclose methods for simultaneously reshaping and coloring hairs in which a keratin-reducing preparation is used that already includes the necessary direct dyes and/or oxidation dye precursors. At least a portion of the respective keratin-reducing preparation is applied to the hair after it has been mechanically deformed. However, the direct dyes and/or oxidation dye precursors used for coloration do not always have satisfactory stability in comparison to the keratin-reducing preparation, so that when the direct dyes and/or oxidation dye precursors react with the keratin-reducing preparation, uneven reshaping and coloring results can occur.
It is therefore the object of the present invention to provide a method for reshaping and coloring keratinic fibers, particularly for human hairs, in which the reshaping and coloration can be performed in a single process and which yields a comparable or better reshaping result, colors the keratinic fibers uniformly in the desired color tone, and causes only slight or even absolutely no hair damage.